我可以从Silverlight中的一个BitmapImage的一个byte []？ [英] Can I get a byte[] from a BitmapImage in Silverlight?

问题描述

我想传递一个图像的某些代表性来回Silverlight和WCF服务之间。如果可能的话，我想传递一个 System.Windows.Media.Imaging.BitmapImage ，因为这将意味着客户不必做任何转换。

I'm trying to pass some representation of an image back and forth between Silverlight and a WCF service. If possible I'd like to pass a System.Windows.Media.Imaging.BitmapImage, since that would mean the client doesn't have to do any conversion.

然而，在某些时候，我需要这个图像存储在数据库中，这意味着图像表示必须能够转换和从字节[] 。我可以创建一个的BitmapImage 从字节[] 通过读取阵列成 MemoryStream的，并使用 BitmapImage.SetSource（）。但我似乎无法找到一种方法，另一种方式转换 - 从的BitmapImage 到字节[] 。我失去了一些东西明显在这里？

However, at some point I need to store this image in a database, meaning the image representation must be able to convert to and from byte[]. I can create a BitmapImage from a byte[] by reading the array into a MemoryStream and using BitmapImage.SetSource(). But I can't seem to find a way to convert the other way - from BitmapImage to byte[]. Am I missing something obvious here?

如果它有助于在所有的转换代码可以在服务器上运行，也就是说，它并不需要是Silverlight的安全。

If it helps at all, the conversion code could run on the server, i.e. it doesn't need to be Silverlight-safe.

推荐答案

使用这样的：

public byte[] GetBytes(BitmapImage bi)
{
    WriteableBitmap wbm = new WriteableBitmap(bi);
    return wbm.ToByteArray();
}

其中，

Where

public static byte[] ToByteArray(this WriteableBitmap bmp)
{
    // Init buffer
    int w = bmp.PixelWidth;
    int h = bmp.PixelHeight;
    int[] p = bmp.Pixels;
    int len = p.Length;
    byte[] result = new byte[4 * w * h];

    // Copy pixels to buffer
    for (int i = 0, j = 0; i < len; i++, j += 4)
    {
        int color = p[i];
        result[j + 0] = (byte)(color >> 24); // A
        result[j + 1] = (byte)(color >> 16); // R
        result[j + 2] = (byte)(color >> 8);  // G
        result[j + 3] = (byte)(color);       // B
    }

    return result;
}

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